1. Field of the Invention
This invention relates to a liquid arresting method and apparatus for refrigeration systems, and, more particularly, to a valve device for use in the intake flow path of a refrigerant compressor, and to a method for preventing passage of liquid phase refrigerant into the compressor.
2. Description of the Related Art
In conventional mechanical refrigeration systems, a compressor circulates refrigerant through a condenser in which a refrigerant is cooled and liquified, an expansion device and an evaporator in which the liquid refrigerant is flashed into vapor, and then returned to the compressor. Although under ideal operating conditions, only vapor phase refrigerant is passed to the intake of the compressor, it is common, under less than ideal conditions, for liquid containing refrigerant to pass into the compressor intake.
The potential for damage to such components of the compressor as bearing and valves, resulting from intake of liquid refrigerant, has been addressed in the past by one of either over-design of compressor components so that they are not damaged by expected liquid refrigerant intake, or by a restriction in the flow line up stream of the compressor intake, so that upon passing the restriction, any liquid phase refrigerant flashes into vapor to be drawn into the compressor intake. Both of these approaches have disadvantages. Over designing the compressor components entails increased compressor manufacturing costs, whereas use of restriction in the compressor intake lowers efficiency of the overall system.
In light of the foregoing, there is a need for a low cost, efficient solution to liquid phase refrigerant intake to the compressor of a mechanical refrigeration system.
The advantages and purpose of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages and purpose of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
To attain the advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention is directed to a liquid arresting valve for a refrigeration compressor having a refrigerant intake. The valve includes a housing having an inlet end to receive liquid and vapor phase refrigerant from an evaporator and an outlet end for connection to the refrigerant intake of the compressor. A valve body is movable in the housing between an open position permitting substantially unrestricted flow of vapor phase refrigerant between the inlet and outlet ends of the housing, and a flow restricting position to cause liquid containing refrigerant entering the inlet end of the housing to exit through the outlet end of the housing as vapor phase refrigerant.
In another aspect, the invention is directed to a method for arresting liquid from a refrigeration compressor intake, comprising the steps of enabling substantially unrestricted flow of vapor phase refrigerant to the compressor intake when the refrigerant flowing to the compressor intake is substantially free of liquid refrigerant, and restricting flow of refrigerant containing liquid to the compressor intake, and thereby flashing the liquid refrigerant into vapor prior to reaching the compressor intake when the refrigerant flowing to the compressor intake includes more than a predetermined acceptable amount of liquid refrigerant. The restriction step is initiated by response to increased density of refrigerant containing liquid.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.